Abstract: Aiming at the present imperfect status of fracture pressure calculation model for directional wells,the research on the fracture pressure of arbitrary well deviation and azimuth has been carried out.According to the fracture pressure calculation principles and relative theories of ellipse,the fracture pressure calculation formulas of different well deviation and azimuth for deviated wells and horizontal wells have been established.With the derived calculation method,the fracture pressures of target layers for different well types havebeen calculated.Compared with the measured data of site construction,the relative error is less than 5%,which shows that this calculation method is of high reliability.